Re: [ROOT] debugging ROOT with gdb

From: Brett Viren (bv@bnl.gov)
Date: Tue Jun 04 2002 - 20:12:21 MEST


Christian Holm Christensen writes:
 > Brett Viren <bv@bnl.gov> wrote
 > >  - run GDB 5.x for better C++ support.  v4 is pretty bad with C++.
 > 
 > Ah, someone is running Debian GNU/Linux testing at least :-) 

Guilty.  "Sid", actually.

 > >  - set a break in main(), hit it, set the break you really want and
 > >  then "continue".  This gets around spurious "can not do i/o"
 > >  (message paraphrased) GDB error.
 > 
 > Erh, I think that's a very kind paraphrase of that error message.
 > However, it does make sense - obviously you can not set a breakpoint
 > on a symbol before that symbol is defined, and it may not be defined
 > until you `dlopen' it. 

No, this isn't the problem I tried to describe.  The problem is that
at times I *successfully* set a break point, it is reached, I get the
"(gdb)" prompt and as soon as I type something GDB *dies* (exits) with
the error message "i/o impossible" or something similar.

Next time it happens I'll try to remember to post details.  I always
assumed (uneducated guess) it was some impedance mismatch between
ROOT's and GDB's terminal handling.  For whatever reason, setting a
break in main, hitting it, and then setting the actual break and then
hitting it succeeds.

 > > It would be nice to collect all these things in the root manual
 > > (maybe they are there, I haven't looked recently).
 > 
 > Well, one could also look in the GDB manual :-) 

Oh, you be quiet! <grin>

-Brett.



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